Making this TED-Ed video required (a) a lot of knitting and (b) a ton of boxes of Nerds.

When it came time to animate the lesson “How do cancer cells behave differently from healthy ones?” from educator George Zaidan, our TED-Ed animators had a crazy idea for how to make cell division come alive — using seeds and beans to animate what healthy cells look like as they divide in an orderly pattern and brightly colored candies to show how cancer cells divide quickly and wildly. They also had a good idea for how to show the way cells make up organs of the body—yarn, some knotted, some spooled, some purled and some crocheted.

Sure, cancer doesn’t sound like the most fun topic for an animation. But this lesson explains how chemotherapy works, and why it has such terrible side effects — showing how cancer’s strength is also its weakness. And because the process of making this animation was so fascinating, we asked director Biljana Labovic and animator Lisa Labracio to tell us about how they arrived at this approach.

Nerds? Seeds?Tell us a bit about the visual inspiration and your choice of materials.

Biljana: “It’s all about growth.” That line from the script inspired me to start thinking how I could make cells physically GROW. Materializing them out of something physical seemed like a good starting point, and seeds seemed like a perfect symbolic material to represent the idea of growth. So I started looking at different type of seeds. Some were too small or too big to animate. Eventually, I expended into grains to create a variety of colors, textures and sizes to play with. I went from white couscous to dark azuki beans, and stayed in the range of brown tones — natural food colors. Combining the seeds and grains allowed us to create a variety of different looking cells, but we ended up using only two — hair cells and liver cells.

Once we animated the healthy seed cell, I wanted apply the same philosophy and visual style to creating a cancer cell. The first thing that came to my mind was candy — food full of processed sugar. My original idea was to use different kinds of jelly beans, but they were a little too big compared to our seeds, so I decided to go with Nerds. Their texture and size was much easier to handle for animation. In contrast to the natural seeds and grains, the colors were very unnatural. In addition, we later digitally adjusted the colors to make them feel even more off.

How did you turn the individual pieces into moving, dividing cells?

Lisa: I began by watching several microscopic videos of cell division, which I used as a reference to create a hand-drawn line animation to serve as a guide for my stop-motion animation. With the cancer cell, for example, the purple candies were gathered together as the nucleus, which were surrounded by multi-colored candies as the cytoplasm. Using a series of tools — including chopsticks and tweezers — I moved the candy bits individually into each position of cell division. After each cell was in place, I would take a picture. All of these steps were done by hand, with a camera and stop-motion software to capture the individual frames.

Did you have to do more digital animation?

Lisa: I shot all of the stop-motion animation against a green screen. This was important, because later when you see several cells dividing on screen at once, I was able to duplicate animation in order to fill the screen with cells. Then, in the scene where we portrayed the effects of chemotherapy on liver, hair, AND cancer cells while all were simultaneously dividing, I was able to shoot the individual cell divisions, and composite them as a whole. This saved me from having to organize and shoot all of that animation under the camera at once, which could literally take weeks! Also, the cell membranes — which were doilies for the healthy cells and plastic plates for the cancer cells — were animated and incorporated with the cell animation in the computer.

How did you design the human body?

Biljana: I started to think of the human body and organs as a very delicate creation and, once again, I wanted to use natural organic materials for everything healthy. Yarn came to mind. I was going through some stock footage of yarn patterns and knitted or crouched ornaments, making a parallel to how each organ is a carefully “knitted” object. I came across a multi-colorful twined ball of yarn and this perfectly represented the brain. Then we put knitted gloves for the hands. Our artist Celeste “digitally crocheted” a few organs like the stomach and lungs using Photoshop. We took photographs of twisted yarn for the intestines, etc. The rest of the body had a nice wavy purl pattern representing the blood flowing.

What were you hoping to communicate to your young TED-Ed audience with this video?

Biljana: During the early development period for this animation, I was reading a lot about cell division, cancer and chemotherapy, but I was also thinking a lot about healthy lifestyles and foods, and how to convey that message in this video. I was hoping that I could inspire our young audience, perhaps even subconsciously, to be more aware of the food they eat — especially processed sugar. Interestingly enough, the conversations and debates over healthy diet and vegetarianism vs. eating meat exploded on our YouTube channel within minutes of the video being posted. The message apparently came through.